U.S. patent application number 17/447055 was filed with the patent office on 2022-03-10 for face features matching based tracker.
This patent application is currently assigned to CORSIGHT .AI. The applicant listed for this patent is CORSIGHT .AI. Invention is credited to Keren-Or Curtis, Matan Noga, Ran Vardimon.
Application Number | 20220075997 17/447055 |
Document ID | / |
Family ID | 1000005879196 |
Filed Date | 2022-03-10 |
United States Patent
Application |
20220075997 |
Kind Code |
A1 |
Vardimon; Ran ; et
al. |
March 10, 2022 |
FACE FEATURES MATCHING BASED TRACKER
Abstract
Systems, and method and computer readable media that store
instructions for features matching based tracker.
Inventors: |
Vardimon; Ran; (Tel Aviv,
IL) ; Curtis; Keren-Or; (Rishon LeTsiyon, IL)
; Noga; Matan; (Tel Aviv, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CORSIGHT .AI |
Tel Aviv |
|
IL |
|
|
Assignee: |
CORSIGHT .AI
Tel Aviv
IL
|
Family ID: |
1000005879196 |
Appl. No.: |
17/447055 |
Filed: |
September 7, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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63075246 |
Sep 7, 2020 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06V 20/46 20220101;
G06K 9/6215 20130101; G06V 40/172 20220101; G06V 40/168
20220101 |
International
Class: |
G06K 9/00 20060101
G06K009/00; G06K 9/62 20060101 G06K009/62 |
Claims
1. A method for face features matching based tracker, the method
comprises: receiving, by a tracker, one or more current face
signatures of one or more faces that appear in a current segment of
a video stream; determining a relationship between at least the one
or more current face signatures to at least one or more previous
face signatures, each previous face signature is of a face that
appeared in at least one previous segment of the video stream;
performing current face signature processing for each current face
signature of the one or more current face signatures, the current
face signature processing comprises: allocating the current face
signature to an existing appearance of a face represented by the
previous face signature when the current face signature and the
previous face signature are similar to each other; and associating
the current face signature to a new appearance when the current
face signature is not similar to any of the one or more previous
face signatures.
2. The method according to claim 1 comprising repeating the steps
of receiving, determining and performing for at least one other
current segment of the video stream.
3. The method according to claim 1 wherein each face signature is
associated with a time stamp indicative of a time in which the face
appeared in the video stream; wherein the method comprises
terminating an appearance of a face after a lapse of a predefined
time gap from a last time in which the face appeared in the video
stream.
4. The method according to claim 3 comprising erasing face
signatures of deleted appearances.
5. The method according to claim 1 comprising maintaining up to a
predefined number of face signatures per appearance.
6. The method according to claim 1 comprising maintaining per
appearance, face signatures associated with the appearance, timing
information regarding when a face appeared in the video stream, and
an appearance identifier.
7. The method according to claim 1 comprising associating up to a
single face signature per video stream frame and per
appearance.
8. The method according to claim 1, wherein the determining of the
relationship between the one or more current face signatures to the
one or more previous face signatures comprises searching for a best
matching previous face signatures per current face signature.
9. The method according to claim 1 wherein the determining of the
relationship comprises determining the relationship between (a) the
one or more current face signatures and one or more additional
attributes associated with the one or more current face signatures,
and (b) the at least one previous face signatures and at least one
additional attribute associated with the at least one previous face
signature.
10. The method according to claim 1 wherein the determining of the
relationship comprises: performing a first phase of determining
similarities between a current face signature to the one or more
previous face signatures; when no previous face signature of the
one or more previous face signature is similar, then performing a
second phase of determining similarities between (a) the current
face signature and at least one additional attribute associated
with the current face signature, and (b) the at least one previous
face signatures and at least one additional attribute associated
with the at least one previous face signature.
11. The method according to claim 10 comprises applying a first
similarity criterion between the current face signature and the one
or more previous face signatures during the first phase, and
applying a second similarity criterion between the current face
signature and the one or more previous face signatures during the
second phase, wherein the second similarity criterion is more
relaxed.
12. A non-transitory computer readable medium that stores
instructions for: receiving, by a tracker, one or more current face
signatures of one or more faces that appear in a current segment of
a video stream; determining a relationship between at least the one
or more current face signatures to at least one or more previous
face signatures, each previous face signature is of a face that
appeared in at least one previous segment of the video stream;
performing current face signature processing for each current face
signature of the one or more current face signatures, the current
face signature processing comprises: allocating the current face
signature to an existing appearance of a face represented by the
previous face signature when the current face signature and the
previous face signature are similar to each other; and associating
the current face signature to a new appearance when the current
face signature is not similar to any of the one or more previous
face signatures.
13. The non-transitory computer readable medium according to claim
12 wherein each face signature is associated with a time stamp
indicative of a time in which the face appeared in the video
stream; wherein the non-transitory computer readable medium
comprises terminating an appearance of a face after a lapse of a
predefined time gap from a last time in which the face appeared in
the video stream.
14. The non-transitory computer readable medium according to claim
12 that stores instructions for maintaining up to a predefined
number of face signatures per appearance.
15. The non-transitory computer readable medium according to claim
12 that stores instructions for maintaining per appearance, face
signatures associated with the appearance, timing information
regarding when a face appeared in the video stream, and an
appearance identifier.
16. The non-transitory computer readable medium according to claim
12 that stores instructions for associating up to a single face
signature per video stream frame and per appearance.
17. The non-transitory computer readable medium according to claim
12, wherein the determining of the relationship between the one or
more current face signatures to the one or more previous face
signatures comprises searching for a best matching previous face
signatures per current face signature.
18. The non-transitory computer readable medium according to claim
12 wherein the determining of the relationship comprises
determining the relationship between (a) the one or more current
face signatures and one or more additional attributes associated
with the one or more current face signatures, and (b) the at least
one previous face signatures and at least one additional attribute
associated with the at least one previous face signature.
19. The non-transitory computer readable medium according to claim
12 wherein the determining of the relationship comprises:
performing a first phase of determining similarities between a
current face signature to the one or more previous face signatures;
when no previous face signature of the one or more previous face
signature is similar, then performing a second phase of determining
similarities between (a) the current face signature and at least
one additional attribute associated with the current face
signature, and (b) the at least one previous face signatures and at
least one additional attribute associated with the at least one
previous face signature.
20. A computerized system comprising a processor that is configured
to: obtain, by a tracker, one or more current face signatures of
one or more faces that appear in a current segment of a video
stream; determine a relationship between at least the one or more
current face signatures to at least one or more previous face
signatures, each previous face signature is of a face that appeared
in at least one previous segment of the video stream; perform
current face signature processing for each current face signature
of the one or more current face signatures, the current face
signature processing comprises: allocate the current face signature
to an existing appearance of a face represented by the previous
face signature when the current face signature and the previous
face signature are similar to each other; and associate the current
face signature to a new appearance when the current face signature
is not similar to any of the one or more previous face signatures.
Description
BACKGROUND
[0001] There is a growing need to track after appearances of
persons in video streams. A typical solution processes one frame at
a time--trying to find at the frame a set of pixels that will match
a reference signature of a face.
[0002] Such tracking is susceptible to changes that may occur
between one frame to another such as--changes in illumination
conditions, changes in spatial relationship between the face to the
image sensor, mixing between adjacent faces, and the like.
[0003] There is a growing need to provide a more robust tracking
method.
SUMMARY
[0004] There may be provided systems, methods and computer readable
medium as illustrated in the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The embodiments of the disclosure will be understood and
appreciated more fully from the following detailed description,
taken in conjunction with the drawings in which:
[0006] FIG. 1 illustrates an example of a method;
[0007] FIG. 2 is an example of a system; and
[0008] FIG. 3 is an example of images and metadata.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0009] In the following detailed description, numerous specific
details are set forth in order to provide a thorough understanding
of the invention. However, it will be understood by those skilled
in the art that the present invention may be practiced without
these specific details. In other instances, well-known methods,
procedures, and components have not been described in detail so as
not to obscure the present invention.
[0010] The subject matter regarded as the invention is particularly
pointed out and distinctly claimed in the concluding portion of the
specification. The invention, however, both as to organization and
method of operation, together with objects, features, and
advantages thereof, may best be understood by reference to the
following detailed description when read with the accompanying
drawings.
[0011] It will be appreciated that for simplicity and clarity of
illustration, elements shown in the figures have not necessarily
been drawn to scale. For example, the dimensions of some of the
elements may be exaggerated relative to other elements for clarity.
Further, where considered appropriate, reference numerals may be
repeated among the figures to indicate corresponding or analogous
elements.
[0012] Because the illustrated embodiments of the present invention
may for the most part, be implemented using electronic components
and circuits known to those skilled in the art, details will not be
explained in any greater extent than that considered necessary as
illustrated above, for the understanding and appreciation of the
underlying concepts of the present invention and in order not to
obfuscate or distract from the teachings of the present
invention.
[0013] Any reference in the specification to a method should be
applied mutatis mutandis to a device or system capable of executing
the method and/or to a non-transitory computer readable medium that
stores instructions for executing the method.
[0014] Any reference in the specification to a system or device
should be applied mutatis mutandis to a method that may be executed
by the system, and/or may be applied mutatis mutandis to
non-transitory computer readable medium that stores instructions
executable by the system.
[0015] Any reference in the specification to a non-transitory
computer readable medium should be applied mutatis mutandis to a
device or system capable of executing instructions stored in the
non-transitory computer readable medium and/or may be applied
mutatis mutandis to a method for executing the instructions.
[0016] Any combination of any module or unit listed in any of the
figures, any part of the specification and/or any claims may be
provided.
[0017] The specification and/or drawings may refer to an image. An
image is an example of a media unit. Any reference to an image may
be applied mutatis mutandis to a media unit. A media unit may be an
example of sensed information unit. Any reference to a media unit
may be applied mutatis mutandis to sensed information. The sensed
information may be sensed by any type of sensors--such as a visual
light camera, or a sensor that may sense infrared, radar imagery,
ultrasound, electro-optics, radiography, LIDAR (light detection and
ranging), etc.
[0018] The specification and/or drawings may refer to a processor.
The processor may be a processing circuitry. The processing
circuitry may be implemented as a central processing unit (CPU),
and/or one or more other integrated circuits such as
application-specific integrated circuits (ASICs), field
programmable gate arrays (FPGAs), full-custom integrated circuits,
etc., or a combination of such integrated circuits.
[0019] Any combination of any steps of any method illustrated in
the specification and/or drawings may be provided.
[0020] Any combination of any subject matter of any of claims may
be provided.
[0021] Any combinations of systems, units, components, processors,
sensors, illustrated in the specification and/or drawings may be
provided.
[0022] The analysis of content of a media unit may be executed by
generating a signature of the media unit and by comparing the
signature to reference signatures. The reference signatures may be
arranged in one or more concept structures or may be arranged in
any other manner. The signatures may be used for object detection
or for any other use.
[0023] The term "substantially" means insignificant deviation--for
example differences that do not exceed few percent of a value,
differences that are below the accuracy and/or resolution related
to the face recognition process. What is substantially may be
defined in any manner.
[0024] The term "segments of a video stream" may be one or more
frames of the video streams.
[0025] There may be provided a matching based tracker for tracking
after a face.
[0026] There may be provided a method that uses features from a
model trained for face recognition, using similarity matching with
either embeddings or binarized signatures. The method may use
features trained to recognize faces, not just the existence of face
(e.g. face detector), this gives an entirely different level of
quality for such tracking.
[0027] The tracking may be configured to track after a person even
when the person changes his appearance during the video. The method
may track faces in dense crowds even with head bobbing (queues of
people facing the camera). The tracker may track a person that
leaves the field of view of the image sensor (that acquired the
video stream) and then re-enters the video frame, or being occluded
for some time.
[0028] The tracker may avoid confusion between similar looking
persons.
[0029] An appearance is an ongoing identification of a specific
individual in a specific video stream. It may begin once a new face
is detected in a frame, and ends if the face did not appear in any
following frame for a preconfigured time period (TTL). The
appearance may be associated with a sequence of detected faces and
their signatures.
[0030] It may be beneficial to have a tracker that is dedicated to
tracking faces--and may not be configured to track other
objects.
[0031] It is assumed that face signatures of the same face do not
extensively change between adjacent frames.
[0032] It is beneficial to apply the tracker on a video stream that
is not significantly altered (for example different frames do not
undergo different graphic image processing insertion
processes).
[0033] FIG. 1 illustrates an example of method 100.
[0034] Method 100 may start by step 110 of receiving, by a tracker,
one or more previous face signatures of one or more faces that
appear in a current segment of a video stream.
[0035] The current segment may be the first frame of the video, and
if so--there may or may not be any previous face signatures.
[0036] It is assumed that step 110 includes receiving one or more
previous face signatures. This may occur after faces appeared in
one or more frames of the video stream and one or more previous
face signatures were generated.
[0037] Step 110 may be preceded by or may include generating face
signatures by a signature generator. The signature generator may
differ from the tracker, may be integrated with the tracker, may be
implemented by the same processing circuit, may be implemented by a
different processing circuit than the signature generator, and the
like.
[0038] Non-limiting examples of signature generator and searching
for similar (for example matching) signatures is illustrated in
U.S. patent application Ser. No. 16/544,940 filing date Aug. 20,
2019 which is incorporated herein by reference.
[0039] Step 110 may be followed by step 120 of determining a
relationship between the one or more current face signatures to one
or more previous face signatures, each previous face signature is
of a face that appeared in at least one previous segment of the
video stream.
[0040] The determining may include searching, for each current face
signature of the one or more current face signatures, a previous
face signature that is similar to the current face signature. One
previous face signature may be selected per current face
signature--and it may be the most similar previous face
signatures.
[0041] The determining may include determining that a current face
signature does not have any matching previous face signatures.
[0042] The determining may include searching for a previous face
signature that is similar to a current face signature based on the
visual attributes alone (for example based on the signature
alone).
[0043] Additionally or alternatively--the determining may include
searching for a previous face signature that is similar to a
current face signature based on the visual attributes alone and at
least one additional attribute. The at least one additional
attribute may include location of the face and/or time of
appearance of the face in the video stream.
[0044] Step 120 may include step 122 of searching, for each current
face signature of the one or more current face signatures, for a
previous face signature that is similar to the current face
signature. The similarity is based only on the face signatures.
Step 122 may be regarded as a first phase.
[0045] Step 120 may include step 124 of searching, for each current
face signature of the one or more current face signatures, for a
previous face signature that is similar to the current face
signature. The similarity is based on the face signatures and on
one or more additional attributes. Step 124 may be regarded as a
second phase.
[0046] Step 124 may include relaxing the similarity threshold--for
example allowing less similar face signatures to be regarded as
belonging to the same face.
[0047] Step 120 may include first applying step 122--and if no
similarity signature is found applying step 124--especially with a
more relaxed similarity threshold.
[0048] The similarity between signatures may be any similarity
text--for example overlap between signatures, any distance between
signatures, and the like.
[0049] Step 120 may be followed by step 130 of performing current
face signature processing for each current face signature of the at
one or more current face signatures.
[0050] For a current face signature that has a similar (especially
most similar) previous face signature--step 130 may include step
132 of allocating the current face signature and a previous face
signature to an existing appearance of a face represented by the
previous face signature.
[0051] For a current face signature that does not have a similar
previous face signature--step 130 may include step 134 of
associating the current face signature to a new appearance.
[0052] Step 120 may also be followed by step 140 of performing
appearance management.
[0053] Step 140 may include step 142 of terminating an appearance
if a face associated with the appearance does not appear in the
video stream for at least a predefined period. Thus--step 140 may
include terminating an appearance if there is a sufficient time gap
from a last time in which the face appeared in the video
stream.
[0054] Step 140 may include step 144 of deleting the previous face
signatures of this appearance.
[0055] Each face signature (current face signatures, previous face
signature) may be associated with a time stamp indicative of a time
in which the face appeared in the video stream. Step 140 may
determine whether the time gap has lapsed, based, at least in part,
on the time stamps.
[0056] The method (for example--step 140) may include maintaining
up to a predefined number (N1) of face signatures per appearance.
For example--the last N1 face signatures.
[0057] The method (for example--step 140) may include maintaining
per appearance, face signatures associated with the appearance,
timing information regarding when a face appeared in the video
stream, and an appearance identifier.
[0058] Steps 110, 120, 130 and 140 may be repeated for multiple
segments of the video stream. Each iteration processes current face
signatures of a current segment, and when the iteration ends this
current segment becomes a previous segment and the current face
signatures become the previous face signatures.
[0059] If, for example, a segment is a single frame, then each
iteration includes receiving one or more face signatures from this
frame (if such exist), and executing steps 120, 130 and 140 in
relation to this frame. The next iteration will be applied on face
signatures of the next frame.
[0060] FIG. 2 illustrates an example of a computerized system 400.
The computerized system may be configured to execute method
100.
[0061] The computerized system may include a processor 410 that may
include one or more processing circuits, a memory unit 420 and an
input output unit 430. The memory unit 420 is configured to store
commands, intermediate data, match results, and the like. The input
output unit 430 may receive information and may output information.
The processor 410 may be a neural network processor, may implement
instructions that once executed perform CNN processing, and the
like. The computerized system may be one or more computers, may be
located in the cloud, may be located in any place and may be
adapted to receive information over any network.
[0062] The processor 410 may implement a signature generator 411
and a tracker 412. It should be noted that the tracker 412 and the
signature generator may be implemented by different processors. The
system 400 may be fed with video streams from one or more image
sensors. Additional attributes such as location and/or time may be
generated by stream 100 or received by system 400. Any method for
generating location information and/or timing information may be
used.
[0063] FIG. 3 illustrates various images and metadata.
[0064] A first frame 300(1) includes a first face 301.
[0065] There are no previous face signatures. The first frame is
processed to provide a first current face signature CS(F1)
311(1).
[0066] There is a first appearance A(F1) 315.
[0067] There are also provided and one or more first additional
attributes AD(F1) 312(1) such as Timing(F1) 313(1) indicative of
the timing of the first frame, and Location(F1) 314(1) indicative
of the location of the first face--for example physical location
(street address, GPS coordinates and the like).
[0068] A second frame 300(2) includes a second face 302.
[0069] There is a previous face signature PS(F1) 311'(1) and
previous additional attributes AD'1(F1) 312'(1) generated from the
first frame and related to the first face. The second frame is
processed to provide a second current face signature CS(F2)
321(2).
[0070] There is a first appearance A(F1) 315 and a second
appearance A(F2) 325.
[0071] There are also provided and one or more second additional
attributes AD(F2) 322(2) such as Timing(F2) 323(2) indicative of
the timing of the second frame, and Location(F2) 314(2) indicative
of the location of the second face--for example physical location
(street address, GPS coordinates and the like).
[0072] A third frame 300(3) includes the first face 301 and the
second face 302. The third frame is processed to provide first
current face signature CS(F1) 311(1) a second current face
signature CF(F2) 321(2).
[0073] There is a first appearance A(F1) 315 and a second
appearance A(F2) 325.
[0074] There is a previous face signature PS(F1) 311'(1) and
previous additional attributes AD'1(F1) 312'(1) generated from the
first frame and related to the first face.
[0075] There is a previous face signature PS(F2) 321'(2) and
previous additional attributes AD'(F2) 322' (2) generated from the
second frame and related to the second face.
[0076] There are also provided and one or more first additional
attributes AD(F1) 312(3) related to the third frame--such as such
as Timing(F1) 313(3) indicative of the timing of the third frame,
and Location(F1) 314(3) indicative of the location of the first
face.
[0077] There are also provided and one or more second additional
attributes AD(F2) 322(3) related to the third frame such as
Timing(F2) 323(3) indicative of the timing of the third frame, and
Location(F2) 324(3) indicative of the location of the second
face.
[0078] It should be noted that that current face signature CS(F1)
3141) from frame 3 is similar to previous face signature PS(F1)
311'(1) from frame 1, and that's why face 301 on frame 3 is
assigned the same appearance A(F1) 315
[0079] The following table illustrates an example of frames,
current face signatures (SC(Fx)), previous face signatures
(PS(Fx)), open appearances (A(Fx)). Index x represents a face. In
the example there are illustrated five faces--first face F1, second
face F2, third face--F3, fourth face F4 and fifth face F5.
[0080] In the following example an appearance is terminated after
two hundred frames in which the face did not appear in a frame.
See, for example, the appearance of the third face A(F3) is
terminated after two hundred frames (at the 207'th frame) from the
last appearance of the face (at the seventh frame). See, for
example appearance of the second face A(F2) is terminated after two
hundred frames (at the 206'th frame) from the last appearance of
the face (at the sixth frame).
TABLE-US-00001 TABLE 1 Frame Previous face Current face Relevant #
signatures signatures appearances 1 -- CS(F1) A(F1) 2 PS(F1) CS(F1)
A(F1) 3 PS(F1) CS(F2), CS(F1) A(F1), A(F2) 4 PS(F1), PS(F2) CS(F2)
A(F1), A(F2) 5 PS(F1), PS(F2) CS(F2), CS(F3) A(F1), A(F2), A(F3) 6
PS(F1), PS(F2), CS(F1), CS(F2), A(F1), A(F2), PS(C3) CS(F3) A(F3) 7
PS(F1), PS(F2), CS(F1), CS(F3), A(F1), A(F2), PS(C3) CS(F4) A(F3) 8
PS(F1), PS(F2), CS(F1), CS(F4) A(F1), A(F2), PS(F3), PS(F4) A(F3),
A(F4) 9 PS(F1), PS(F2), CS(F1), CS(F4) A(F1), A(F2), PS(F3), PS(F4)
A(F3), A(F4) 10 PS(F1), PS(F2), CS(F1), CS(F4) A(F1), A(F2),
PS(F3), PS(F4) A(F3), A(F4) 205 PS(F1), PS(F2), CS(F1), A(F1),
A(F2), PS(F3), PS(F4) A(F3), A(F4) 206 PS(F1), PS(F3), CS(F1),
CS(F5) A(F1), A(F3), PS(F4) A(F4), A(F5) 207 PS(F1), PS(F4),
CS(F1), A(F1), A(F4), PS(F5) A(F5) 208 PS(F1), PS(F4), CS(F1),
CS(F2) A(F1), A(F2), PS(F5) A(F4), A(F5)
[0081] While the foregoing written description of the invention
enables one of ordinary skill to make and use what is considered
presently to be the best mode thereof, those of ordinary skill will
understand and appreciate the existence of variations,
combinations, and equivalents of the specific embodiment, method,
and examples herein. The invention should therefore not be limited
by the above described embodiment, method, and examples, but by all
embodiments and methods within the scope and spirit of the
invention as claimed.
[0082] In the foregoing specification, the invention has been
described with reference to specific examples of embodiments of the
invention. It will, however, be evident that various modifications
and changes may be made therein without departing from the broader
spirit and scope of the invention as set forth in the appended
claims.
[0083] Moreover, the terms "front," "back," "top," "bottom,"
"over," "under" and the like in the description and in the claims,
if any, are used for descriptive purposes and not necessarily for
describing permanent relative positions. It is understood that the
terms so used are interchangeable under appropriate circumstances
such that the embodiments of the invention described herein are,
for example, capable of operation in other orientations than those
illustrated or otherwise described herein.
[0084] Furthermore, the terms "assert" or "set" and "negate" (or
"deassert" or "clear") are used herein when referring to the
rendering of a signal, status bit, or similar apparatus into its
logically true or logically false state, respectively. If the
logically true state is a logic level one, the logically false
state is a logic level zero. And if the logically true state is a
logic level zero, the logically false state is a logic level
one.
[0085] Those skilled in the art will recognize that the boundaries
between logic blocks are merely illustrative and that alternative
embodiments may merge logic blocks or circuit elements or impose an
alternate decomposition of functionality upon various logic blocks
or circuit elements. Thus, it is to be understood that the
architectures depicted herein are merely exemplary, and that in
fact many other architectures may be implemented which achieve the
same functionality.
[0086] Any arrangement of components to achieve the same
functionality is effectively "associated" such that the desired
functionality is achieved. Hence, any two components herein
combined to achieve a particular functionality may be seen as
"associated with" each other such that the desired functionality is
achieved, irrespective of architectures or intermedial components.
Likewise, any two components so associated can also be viewed as
being "operably connected," or "operably coupled," to each other to
achieve the desired functionality.
[0087] Furthermore, those skilled in the art will recognize that
boundaries between the above described operations merely
illustrative. The multiple operations may be combined into a single
operation, a single operation may be distributed in additional
operations and operations may be executed at least partially
overlapping in time. Moreover, alternative embodiments may include
multiple instances of a particular operation, and the order of
operations may be altered in various other embodiments.
[0088] Also for example, in one embodiment, the illustrated
examples may be implemented as circuitry located on a single
integrated circuit or within the same device. Alternatively, the
examples may be implemented as any number of separate integrated
circuits or separate devices interconnected with each other in a
suitable manner.
[0089] However, other modifications, variations and alternatives
are also possible. The specifications and drawings are,
accordingly, to be regarded in an illustrative rather than in a
restrictive sense.
[0090] In the claims, any reference signs placed between
parentheses shall not be construed as limiting the claim. The word
`comprising` does not exclude the presence of other elements or
steps then those listed in a claim. Furthermore, the terms "a" or
"an," as used herein, are defined as one or more than one. Also,
the use of introductory phrases such as "at least one" and "one or
more" in the claims should not be construed to imply that the
introduction of another claim element by the indefinite articles
"a" or "an" limits any particular claim containing such introduced
claim element to inventions containing only one such element, even
when the same claim includes the introductory phrases "one or more"
or "at least one" and indefinite articles such as "a" or "an." The
same holds true for the use of definite articles. Unless stated
otherwise, terms such as "first" and "second" are used to
arbitrarily distinguish between the elements such terms describe.
Thus, these terms are not necessarily intended to indicate temporal
or other prioritization of such elements. The mere fact that
certain measures are recited in mutually different claims does not
indicate that a combination of these measures cannot be used to
advantage.
[0091] While certain features of the invention have been
illustrated and described herein, many modifications,
substitutions, changes, and equivalents will now occur to those of
ordinary skill in the art. It is, therefore, to be understood that
the appended claims are intended to cover all such modifications
and changes as fall within the true spirit of the invention.
[0092] It is appreciated that various features of the embodiments
of the disclosure which are, for clarity, described in the contexts
of separate embodiments may also be provided in combination in a
single embodiment. Conversely, various features of the embodiments
of the disclosure which are, for brevity, described in the context
of a single embodiment may also be provided separately or in any
suitable sub-combination.
[0093] It will be appreciated by persons skilled in the art that
the embodiments of the disclosure are not limited by what has been
particularly shown and described hereinabove. Rather the scope of
the embodiments of the disclosure is defined by the appended claims
and equivalents thereof.
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